Chapter 1102 Space-based Digital Image Transmission System
October 16, 2003, 6:23.
The Shenzhou-5 return capsule successfully landed in the scheduled return area in central Mongolia Province.
Only 4.8 kilometers from the intended landing center.
This number is quite satisfactory in the reservation plan.
It’s not even the best result in previous recycling.
However, with the two previous accidents in the United States and Russia, the normal situation of Shenzhou 5 does not seem so normal...
The No. 736 helicopter responsible for the search and rescue mission, That is, the helicopter Chang Haonan flew in before quickly landed near the return capsule. The medical team and search and rescue team quickly arrived to help the astronauts open the hatch cover and conduct the first medical examination in the cabin.
Twenty-seven minutes later, China's first astronaut completed the exit independently and confirmed that all physical indicators were normal...
At this time, the atmosphere in the command and control hall was calmer than before. Down a lot.
For many people who have been fighting for this for several years, or even more than ten years, the emotions burst out at this moment cannot be expressed by cheers and celebrations.
According to the plan, the commander-in-chief of the manned space program should officially announce at this time that the Shenzhou-5 mission was a complete success.
But he stood behind the small podium and opened his mouth several times in a row, but he was unable to complete a sentence that he was already familiar with.
Some of the older comrades even had red eyes, but they restrained themselves from showing it because of the cameras surrounding them.
Originally, there is a high probability that Shen Junrong should be included.
But he was diverted by Chang Haonan in advance. After confirming that the Shenzhou 5 return capsule and astronauts were fine, he switched back to the previous topic at the speed of light.
"Comrade Haonan?"
Obviously, as an expert in the field of measurement and control communications, Shen Junrong can no longer get rid of this idea in his mind.
Chang Haonan was also clapping along at this moment. He was called twice by Shen Junrong before he heard someone calling his name, so he quickly turned around.
“You just mentioned changing the shape of the reentry body to a pointed cone shape...but the effective space inside this shape is too low, and more importantly...the high temperature and temperature caused by aerodynamic heating The ablation will be more serious, and there are also problems with the structural strength of the thin-shell cone... About ten years ago, we had a rocket that was successfully launched but the payload was damaged because this structure was used inside the fairing..."
Contrary to many people's intuition, in fluid dynamics, the shape with the lowest resistance is a rounded blunt nose, which is the bulbous bow of an ocean-going ship, or the shape of the return capsule of a manned spacecraft.
The pointed cone will increase the resistance.
"This..."
In fact, what Chang Haonan just put forward was just an idea at most.
Not even an idea.
Taking the pointed cone as an example, it is just because this shape is easier to calculate, and the result will definitely reduce the thickness of the plasma sheath.
So, I really haven’t seriously considered the question raised by Shen Junrong.
After some thought, he spoke again:
“High-temperature ablation can be overcome to some extent by increasing the thickness of the heat-resistant coating, or using technologies such as active cooling. ”
“As for space utilization...”
After answering this, Chang Haonan was still stuck.
In fact, the reason why he thought about the communication problem in the black barrier area had nothing to do with the spacecraft -
After so many years of manned spaceflight, the black barrier area was disconnected A few minutes is not really a big problem.
On the contrary, it is very fatal for ballistic missiles.
As for the warheads of ballistic missiles, they don’t actually care much about space utilization.
The altitude range of 35-80km is exactly the most critical stage of terminal attitude adjustment.
Above 80km, the adjustment accuracy is insufficient.
And the friction itself during the reentry process will cause a certain degree of orbit deviation.
And below 35km...
Ballistic missiles do not slow down and land. The tail speed can reach up to 15-20 times the speed of sound, which is 5-7km per second.
After breaking through the black barrier, it took a few seconds to hit the target.
There is no time to adjust.
However, due to the existence of the black barrier, the warhead can neither passively receive satellite signals nor actively use radar guidance.
So the hit accuracy almost only relies on the gyroscope for orbit calculation.
Except for short- and medium-range missiles that do not leave the atmosphere during the entire process, if the circular probability error is 50 meters, then you are already a hero among heroes.
And if the warhead can be guided using synthetic aperture radar... then the hit accuracy of 50 meters is basically the lower limit.
More importantly, it can also be used to attack active targets.
Such as large ships, or important convoys.
But it is obviously not convenient to disclose these ideas to Shen Junrong.
Fortunately, this is not the only way he thinks about reducing or eliminating the impact of the black barrier.
So quickly change the topic:
"The pointed cone is just an example. In fact, more complex shapes can be used..."
"In addition, towards the plasma Injecting substances into the flow field...such as sulfur hexafluoride, rhenium hexafluoride, or carbon tetrachloride can also effectively reduce the electron density in the plasma sheath. Of course, these need to be placed on the head and sides of the reentry body. Opening holes and designing the channel structure is also a big test for the overall structure..."
After Chang Haonan finished speaking, it took a while before Shen Junrong spoke again.
He turned around curiously, only to find that the other party was holding a notebook in his hand and writing rapidly.
Of course, at this time when everyone is watching, the "not doing business" communication between the two did not last long.
The media who had waited for two days to finally get an interview opportunity swarmed in, and soon someone noticed Chang Haonan and Shen Junrong not far away.
In the blink of an eye, several microphones with different media logos were handed around...
...
A few hours later.
National Aeronautics and Space Administration Headquarters.
Marville strode into the director's office and came to Sean O'Keefe.
There is also a piece of information in his hand:
"Director, the reconnaissance results from the Central Command have been sent back. This is the analysis result."
As he spoke, he opened the document and put it on his desk:
“But...”
Before he finished speaking, O’Keefe took over:
"But no abnormalities were found. There was only one S-band signal source, but the communication capacity was extremely low?"
He did not even lower his head to glance at the report content.
"Uh... That's true, but how did you..."
After the Global Hawk returned, the intelligence was uploaded to China at almost the fastest speed, and was then technically processed by NASA analysts.
There is no additional process.
"Alas..."
O'Keefe shook his head helplessly, pulled out a few pieces of paper from the side of the computer, and handed them to Marville opposite:
"Take a look."
The latter received it and found it was a translated news briefing.
Of course, the originals are also attached.
Chinese.
The content of the top line is——
"my country's first manned space mission was successfully completed, and the space-based digital image transmission system made great achievements"
Although the translation was rather blunt, this title still made Marville feel a little nervous.
The text is not long, but the content is very important.
We have introduced a set of new technologies that allow the spacecraft to directly transmit data to the Beijing Aerospace Command Center for about one-third of the time during orbit, which greatly improves the time the spacecraft is in orbit. Such is the effectiveness of work.
They are sending signals directly to the capital, while you are performing passive reconnaissance missions in Central Asia.
Being able to get useful information is called having a ghost.
"They... just reported it directly?"
Marville is also a veteran in NASA, and he still has some understanding of China's style.
Generally speaking, after a new technology is put into use, it will not be said so straightforwardly.
At least not so fast.
O'Keefe put his arms on the table and stared directly at the unopened report in front of him. He was silent for a while before continuing:
"This news is not for their own people, but for their own people. It’s for us...or, for other countries interested in cooperation..."
(End of this chapter)